Method of bending glass sheets or plates



Dec. 8, 1964 C. F. BINKERT ETAL METHOD OF BENDING GLASS SHEETS OR PLATESOriginal Filed Dec. 10, 1954 IN V EN TORS A TTORNE YS United StatesPatent Oil ice 3,160,491 Patented Dec. 8, 1964 4 Claims. (Cl. 65-107)The present invention relates broadly to the bending of glass sheets orplates, and more particularly to an improved method of positioning aglass sheet to be bent in bending relation to the shaping surface of themold and of guiding the sheet as it is bent into conformity with saidshaping surface.

This application is a division of application Serial No. 474,545, filedDecember 10, 1954.

The present-day production of bent glass sheets requires not onlydifferent and improved types of bending molds, but also new and improvedtypes of coacting mold equipment in order to produce on a commercialscale curved glass sheets of good optical properties and having closedimensional tolerances which eliminates the need for selective fittingand installation.

In the production of curved glass sheets, it is important that the fiatsheet to be bent is accurately positioned over the mold shaping surfaceand guided into conformity therewith during the bending action. This isparticularly the case when the glass sheets are pattern out before beingbent, and when the mold is of the hinged type used to produce relativelysharp curvatures. In such molds, the flat glass sheet is customaritlypositioned in bending relation therewith while the mold is in the openposition. As the mold is passed through a bending furnace, the sheetsoftens and sags downwardly. At the same time, the mold moves from theopen position to the closed position in which the glasssheet is receivedon the mold shaping surface. The sheet locating and guiding meansassociated with the mold must, therefore, be cap able of accuratelydepositing the glass sheet on the mold shaping surface, and also todeposit the sheet in such a manner as to prevent sliding contact withthe shaping surface which might cause the sheet to be marred and produceoptical defects.

Therefore, an important object of the invention is to provide animproved method of bending glass sheets or plates.

Another object of the invention is to provide an improved method ofpositioning and guiding a glass sheet to be bent both before and duringthe bending operation.

Other objects and advantages of the invention will become more apparentduring the course of the following description when taken in connectionwith theaccompanying drawings.

In the drawings wherein like numerals are employed to designate likeparts throughout the same:

FIG. 1 is a perspective view of a rack having mounted thereon a pair ofbending molds produced in accordance with the invention;

FIG. 2 is a partial longitudinal section taken along line 22 of FIG. 1showing the mold in the open position with a glass sheet to be bentmounted thereon;

FIG. 3 is a transverse section taken along line 33 of FIG. 2; and

FIG. 4 is a magnified view of one end of the mold showing theconstruction of the improved locator block associated therewith.

With reference now to the drawings, and particularly to FIG. 1, thebending apparatus herein provided is generally designated by the numeral10 and comprises a sup porting rack 11 upon which are carried a pair ofglass bending molds 12 and 13.

The rack 11 comprises :an open, substantially rectangular tubularframework having opposite end sections 14, and longitudinally disposedside rails 15 connected to said end sections to provide a rigidstructure. Arranged transversely between and secured to the side rails15 intermediate the opposite ends thereof is a tubular bar 16 providedadjacent its ends with oppositely directed, longitudinally extendingarms 17 in the outer ends of which are rotatably carried rods 18 thatparallel bar 16.

In the present embodiment of the invention, the rack 11 is formed tocarry the two molds 12 and 13 wherebywhich will permit their subsequentuse as end lights of a V sectional assembly of two or more parts.

To this end, the molds 12 and 13 are arranged on the rack so that likeparts of each mold will be centrally disposed, while the body of eachmold is oriented at an angle to the horizontal to elevate one end of themold body above the other sothat during the bending operation the glasssheets will, upon softening, settle down upon and conform to thecurvature of the molds in the proper manner. By way of illustration, theadjacent inner ends of the molds 1 2and'13 are arranged on the rack 11so as to be materially lower than the outer ends thereof. To facilitateprocessing of the glass subsequent to bending, such as the tempering ofthe sheets by blasts of air, the side rails 15 of the rack 11 areconcavely curved in their central portion to generally correspond to theangular position of the molds and have their ends 7 formed as horizontalsections 19 which terminate at uprights 20 forming portions of the endframe 14.

Since the molds 12 and 13 are adapted 'to simul- V taneously producesimilar curvatures in'the respective glass sheets, they are ofsubstantially. the same construction and therefore a description of onlyone will be given.

As seen in FIGS. 1 and 2, the mold 12 is of the socalled'hinge type andcomprises two joined sections, an upper or end section 21, and a loweror base section 22, connected together at their inner adjacent ends byhinges generally designated 23. The upper mold'section 21 is formed byopposite inwardly curved side bars 24 and 25 which are angularlyconnected to one another at their side bars is a triangular rail 26havinga shaping surface 27 formed on the upper edge thereof. "The rail26 is formed by spaced inwardly curved rails 28 and 29 con-.

nected together at their outermost ends to form the apex 3d of atriangle and which are securedto the side bars 24 and 25 by rigid webmembers 31. The base mold section 22 is formed by side bars 32 and 33connected together at their outermost ends by a cross car 34. Arrangedwithin the confines of the end and side bars of the base section is athree-piece rail designated in its 1 entirety by the numeral 35 andhaving a shaping surface 36 formed on its upper edge. The rail 35comprises side rail portions 37 and 38 rigidly secured to the side bars32 and 33 by additional web members 31 and hav ing their ends oppositethe hinges 23 connected together by a transverse end rail portion 39.The side portions 37 and 38 of the rail 35, carried by the base sectionof the mold, are substantially a continuation of the rail 26 carried bythe upper section, so that the two rails 26 a and 35 cooperate to form acontinuous closed shaping Arranged within the confines of the basesection 22 are joined by hinges 23. 'Each of the I hinges is formed by ayoke section 41 rigidly secured to outwardly extending Web members 42 atwhich the inner ends of each of the side bars 24 and 25 terminate.Received within each of the yokes 41 are bar portions 43 rigidly securedto-similar outwardly extending web members 44 at which the inner ends ofeach of the base section side bars 32 and 33 terminate. V

a The upper mold section 21 is swingably "supported by means of atransverse rod 45 rigidly secured to the lower edges of the side bars 24and 25 and to the e'ndmost portion of downwardly extending portions 46of the rail 25 which, along with the rail 35, is upwardly. notched atglass sheet is wedged between the top surface a of the guide plate 49andthe adjacent metallic'surface d of the locator block casing 52. Whenso placed, the glass sheet 58 acts as a strut having its one end bearingagainst the surface a of the metallic plate 49 and adjacent 1ocator'block 5d, and the other end against the shaping rail portion 39and locator sleeve 57. This strut-like action maintains the mold in itsopen position prior to beinding, and, to compensate for the increasedlength of the mold while in the open position, the links 47 swing'outwardly.

With themold in the open position and the glass sheet supported thereon,the rack is passed through a bending furnace wherein the glasssheet 58settles downwardly spaced intervals to cut down the gross volume of-themold and thereby lessen the heat furnace.

The oppositeends of the rod 45 project beyond the demands on the bendingend section side bars and are rotatably carried in the lower ends of apair of links 47, each of which is'swingably supported at its upper endabout a pin 4-8 fixed in the horizontal portion 19 of the rack sidebars- The base section ZZ is' similarly supported by the transverse rod18 fixedly attached to the cross bar 34 and which toward themold shapingsurface 46 under the influence of heat and gravity. s

As the glass sheet begins to bend, the base section of the mold, whichis restrained from horizontal or vertical movement by the rotatable rod18, pivots about said rod and the ends of said section adjacent thehinges 23 describe a downward arc of fixed radius. At the'same time, theadjacent ends of the upper section 21, due to their 1 hingedrelationship with the lower section, describe subhas its opposite endsextending outwardly beyond the base section side bars and rotatablysupported in the longitudinally extending arms 17.

At the upward termination point,'or triangular apex of the shapingsurface- 27, there is provided a rectangular guide plate 49 which hasits inner edge notched to stantially the same are. Simultaneouslytherewith, the upper end of the mold section 21 moves upwardly and inwardly, the links 47 accommodating this movement due to their rotatableconnection with their fixed supporting pins 48. Inthe initialmovementof, the mold from the open position of FIG. 2, to the closed position ofFIG; 1, the locator block 50 exerts pressure upon the edge of the glasssheet 58 wedged thereagainst. However, as the, de-

' gree of movement increases, contact between the end 0 receive saidapex, and which is rigidly joined. to the outer surfaces of the rails 28and 29. Alongthe upper end of the platev and on the upper surface athereof, there is provided a substantially rectangular locator block 50which comprises an innercore 51 of suitable heat resistant material,such as marinite, and an outer metallic casing 52 entirely surroundingthe core 51 and spacing it from the upper surface of the guide plate.The block 50 is'secured to the plate by means of bolts 53 having theirheadsseated against the top of the casing 52 and their ends protrudingthrough the'plate .49 and secured thereto bynuts.

As seen in FIG. 4, the upper surface a of the plate 49 is insubstantially the same plane of curvature as the shaping surface. 27 ofthe upper mold section and provides a continuation thereof. In thecentral portion of the guide plate and extending outwardly from the apex30 of the rail 26, there is provided a shallow groove b in the uppersurface a, the purpose of which will be later described. The plate 49 isof sufiicient thickness and is polished on its upper surface a so thatthere is little danger of fusion between a glass sheet to be bent andsaid surface.

of'the glass sheet and the locator block is broken and the end edge ofthe glass sheet slides downwardlyover the surface a of the guide plate49.

His important, therefore, that the metallic casing 52 ofthe locatorblock is not at such a temperature as to cause the glass sheettofusetheretof Therefore, the inner heat resistant'core 51 is provided andsince it contacts the metallic casing 52 and thus slows down the heatabsorption rate thereof, a relatively greater time interval under heatmust elapse before the casing 52 would reach a given temperature ascompared to the time interval required to reach the same temperature ifthe core were not used. Due to the time ofmovernent of the bendingapparatus through a bending furnace, the glass sheet 58 will reachbending temperature much sooner than the T metallic casing 52 having theinsulating core 51 therewithin. Thus, since the locator" block isrelatively cooler, any tendency for the'glass sheettofuse to themetallic casing is hindered or completely eliminated. If only the heatresistant core 51were used, the strut-like: action of On the basesection of the mold and on the transverse rail portion 39 thereof, thereis provided a pair of locators 54 positioned outwardly of said railportion and which preferably are spaced in such a manner as to balancethe weight of aglass sheet to be bent which rests thereon. :hatdisclosed in Patent 2,608,799, issued to E. W. Bab- Each of the locators54 is similar to usted inwardly or outwardly from the adjacent shaping:urface.

In operation, a fiat sheet of glass 58' to be bent is' alaced with itslower end resting on the lower shaping 'ail portion 39 and against thesleeves 57. The central )ortion of the mold is. then lifted upwardlyinto its open gosition as shown in FIG. 2, and the upper end c of theduring its downward travel.

time as the end 0 of the glass sheet reaches the groove 1) the glasssheet before it begins tobend would cause the contacting surface of thecore to spall or chip away.

Therefore, by providing the metallic casing, 52 therearound,'theinsulating effect of the core 51 is combined. 7

with the muchgreater resistance. to wearing afforded by the metalliccasing so that the core 51 and casing 52 c0mplement one anotherand thebetter features of both are obtained by the improved construction hereinprovided.

As previously mentioned, the guide plate 49 has its upper surfacecontoured to conform to the shaping surface 27 and its central portiongrooved immediately adjacent the triangular apex 30. Sincethe'plate isso contoured and grooved, full contact between the sharp edge of theglass sheet and the guide plate is maintained throughout the majorportion of downward travel of the sheet end 0 as the sheet bends tofinal form. Also, be-

cause of' the upwardmovement of the tip'of the mold end section 21-during the mold. closing action, the guide plate 49 presentsacontinuously rotating surface, or plane of curvature, over which theend of the glass sheet moves At substantially the same on theguideplate'surface a, the-mold" is substantially closed and the slight furthermovement to effect complete closing causes the apex portion of the rail25 to engage the under surface of the sheet end 0 and space said undersurface from the guide plate. Thus, the rotating, contoured surface ofthe guide plate moves in a predetermined path which is calculated todeposit the downwardly deflecting glass sheet substantiallysimultaneously over all portions of the mold shaping surface and thusprevents sliding contact which could cause optical defects in the nowbent sheet.

It is to be understood that the form of the invention disclosed hereinis to be taken as the preferred embodiment thereof, and that variouschanges in the shape, size and arrangement of parts may be resorted towithout departing from the spirit of the invention or the scope of thefollowing claims.

We claim:

1. A method of bending a glass sheet into contact with the concavelycurved shaping surfaces of a bending mold, comprising locating saidsheet with one end thereof on and in substantially fixed relation tosaid shaping surfaces and the other end outwardly of and above saidsurfaces, supporting said other end for sliding movement on a lower edgecorner thereof toward said shaping surfaces,

- and sags downwardly intermediate its ends toward the heating saidsheet to a temperature at which it softens shaping surfaces and saidother end slides inwardly toward said surfaces, and rotating said otherend upwardly and inwardly toward said first mentioned end to depositsaid sheet on and into contact with said shaping surfaces withoutrubbing contact between said shaping surface and said sheet.

2. A method as defined in claim 1 in which pressure is applied to saidother end of said sheet before the same begins its sliding movement.

3. A method as defined in claim 1 in which said first mentioned end ismoved downwardly at the same time that said other end is being rotatedupwardly and toward said first mentioned end.

4. A method as defined in claim 1 in which pressure is applied to saidother end when said sliding movement is initiated and said pressure isremoved during said sliding movement.

References Cited in the file of this patent UNITED STATES PATENTS

1. A METHOD OF BENDING A GLASS SHEET INTO CONTACT WITH THE CONCAVELY CURVED SHAPING SURFACES OF A BENDING MOLD, COMPRISING LOCATING SAID SHEET WITH ONE END THEREOF ON AND IN SUBSTANTIALLY FIXED RELATION TO SAID SHAPING SURFACES AND THE OTHER END OUTWARDLY OF AND ABOVE SAID SURFACES, SUPPORTING SAID OUTER END FOR SLIDING MOVEMENT ON A LOWER EDGE CORNER THEREOF TOWARD SAID SHAPING SURFACES, HEATING SAID SHEET TO A TEMPERATURE AT WHICH IT SOFTENS AND SAGS DOWNWARDLY INTERMEDIATE ITS ENDS TOWARD THE SHAPING SURFACES AND SAID OUTER END SLIDES INWARDLY TOWARD SAID SURFACES, AND ROTATING SAID OTHER END UPWARDLY AND INWARDLY TOWARD SAID FIRST MENTIONED END TO DEPOSIT SAID SHEET ON AND INTO CONTACT WITH SAID SHAPING SURFACES WITHOUT RUBBING CONTACT BETWEEN SAID SHAPING SURFACE AND SAID SHEET. 